Here's my list for 3 days solo on the Minnesota North Shore in late spring or summer. I'm right at 25lbs (so not UL) including 7.4lb of consumables. Haven't backpacked in many years, since being a scout leader. But back then, 25lbs would have been hedonistic. Comments welcome.

Some of my thoughts up front:

I'm trying to use what I have where feasible. I know I can drop significant weight in the tent and water filter; perhaps the sleeping bag.

The tent needs to have room for me and my dog. Dog will have her own pack with food and dishes. However, I do want to keep some dog food in my pack in case she loses her pack.

The water filter may come off depending on condition of the streams there. If water is plentiful and moving, I might rely on aqua mira tabs. On the other hand, if I go in summer and water is not plentiful, I'll want a filter and may have to add a 2nd liter of water to my pack. I'd like to replace the water filter with a lighter gravity filter.

If weather is cooler than expected, I may have to add some long underwear.

The reason for the phone is that I'm hiking solo. There is reception in most areas up there.

Your list looks pretty good. You're mostly at the point where going with fewer items and repackaging consumable will save weight. Naturally your shelter gear is heavy but without replacing it you're not going to lose much weight. I'm sure others will recommend how to replace that gear and there's plenty of info on this site in case you already don't have some future gear purchases in mind. So instead I'll focus on what can be changed.

Your "possibles" seem heavy at 7.4oz. For just a 3 day weekend you can probably pare it down quite a bit. Your knee brace and similar luxury items like camera also bump up your weight more than many on this site (kudos for the honesty, many will "neglect" these items in their lists). So in your head you can probably wipe off those few ounces. Drop the book and hike longer! ;).

Your plastic utensils are heavy, you can probably find lighter and cheap/free alternatives from food packaging products. First aid could be dropped to a few pills and tape/bandages for under an ounce for the length of trip.

Again minor savings in weight compared to the several pounds you could shave with a light shelter/sleep system. So as a whole you're gear is pretty good already and will drastically improve when you start replacing the big ticket items. Many people go the opposite route and get super light gear and then still carry 10lbs of junk with them =)

Here are some initial suggestions:
NIX- spare underwear, spare t-shirt, towel (you have a bandana), water filter (you have chemicals already or get some aquamira drops), book, poison ivy soap (already have soap and sanitizer), wind pants (if you are in hiking pants those will work and dry just as well as non waterproof wind pants), tealite candle.
approx total ~ 38 ounces

A few other considerations:
Your “possibilities” seem kinda heavy; pen/paper, duct tape, needle/thread, and a garbage bag could easily weigh in at 4oz.
Your first aid kit is kinda heavy, could easily weigh in at 1oz if you just bring the basics.
You could save weight using window shrink film instead of tyvek for a footprint, or just not use a footprint.
Your toiletries and trowel are kinda heavy. An orange plastic trowel can be cut down to about an ounce. A toothbrush, baking powder/tooth powder and hand sanitizer can easily be 1.5 ounces.
approx total ~ 10 ounces

All together that reduces your pack by 3 pounds at virtually no cost.

As far as replacing gear goes, you could save considerable weight with a different tent, sleeping bag, sleeping pad and pack; however that would require spending some dough.

I agree with Mike: there are many things that, to me anyway, seem unneeded and worthy of being nixed– especially some of the stuff in your "Other" category. Personally, I wouldn't take my cell phone (coverage is rather poor anyway), cash (where can it be spent in the wilderness?), and the garbage bags (have a 1 gal. Ziploc in with your food, and it should hold all the waste).

Here are some other thoughts:

I question your need for a compass–if you're hiking along an established, maintained trail with legible signage, you wouldn't need it.

Having a windscreen with a canister stove is dangerous (we're talking explosion here), unless you have a remote canister stove that distances the canister from the burner.

I'm not sure you'd need both the filter and the Aquamira; there are lighter options for pre-filtration. It might be that you can get away without pre-filtration if the water sources on your route are fast-moving, clear steams.

If you're up to it, take the freezer-bag-cooking plunge: I've bought into it 100%, and now my cookpot is a SnowPeak 600 mL cup with a Ti lid (only 3 oz), which I can drink my coffee out of (hence, no need for a plastic cup), and wash with a few drops of Dr. Bronner's (because all that's every in it are boiling water, coffee, and a little spit). Add in a good plastic spoon (less than 1 oz) and you're good to go.

I agree with what everyone else has said. I'd like to address the "spending some dough" category more specifically.

You wouldn't have to spend a load of money to lighten up a lot (granted "a load" is a relative quantifier). Gear swap is your ally in this regard.

You could look to switch to a Golite Jam 50 if you want to stick with the same company of packs. With some modifications (trimming straps and such) that's easily a drop of 21 oz or so (49 oz with the Quest down to a feasible 28 oz, if not less, with the Jam). I've seen the jam sold for less than $50 on gear swap. Of course you could pick a different pack; this one is just an example.

Your sleeping bag isn't the best, but it certainly isn't awful. If I were you, if I decided to spend money, I would make a pack my priority. The weight-savings-to-cost ratio of buying a tent may not be as high as if you were to buy a pack.

Thanks for the suggestions; I appreciate the comments. Here's my thoughts:

“Possibles” include large trash bag that is used as pack liner plus small one for garbage. I can delete poison ivy soap, take a bit less duct tape, eliminate the bag it's in, and use “golf” pencil. Should shave about 2 oz.

Scrap the water filter unless I'm hiking when water is scarce. When scarce, I won't be able to be too selective about water source. Of course, when scarce (in summer), I might have to increase water load to 2L, which will really add weight, but that's a different story (but don't need 12oz fleece then either). Reduces weight by 12 oz. (after adding 2 oz for some sort of paper filter).

The towel is actually 2 microfiber towels each the size of a washcloth. Can eliminate 1. Can trim first aid kit. Trim trowel. Should save about 4 oz.

I had planned on taking about 1/2 a paperback (with cover ripped off). I can reduce it further. Plus, since I have the paperback pages and the candle, eliminate the firestarters. Should shave 3 oz.

The trail is generally marked so I suppose I could drop the compass, or at least replace it with a smaller keychain style compass. Saves about 1 oz.

I reduced the dog food I plan to carry to 1 meal. Dog carries the rest. Saves 5 oz.
I'll need to keep the knee brace for now. After experience with next trip, might be able to eliminate it or go to a lighter one.

There is cell phone coverage along most of the trail as it parallels a major road along Lake Superior. So not exactly wilderness (as would be the case in the BWCA). I consider it a safety tool for a 60-something guy hiking solo. Cash probably isn't necessary unless I chose to take a shuttle back to my starting point.

I'm aware of the issue of a windscreen and a canister stove. I position mine a bit away and only on 2 sides. I haven't noticed the canister getting hot at all with the pot I use.

After all this, my pack weight is 23.25 lbs including 6.8 consumable. If I were to go in early spring where nights are colder, I might have to add 20 oz for a heavier sleeping bag. But still under 25 lbs.

Longer term, I can save about 20 oz on tent plus maybe 16oz on pack, bringing my baseweight to about 14 lbs. But I'll hold off on that for now.

above and beyond what I already mentioned, I would advocate not using a paper pre-filter; they don't work well. If you need a prefilter use a complementary disposable nylon sock from a shoe store, they look like a pantyhose ankle sock (less than .1 ounce) and they are free from your local shoe store = )

So after making changes, my baseweight has dropped from 18.71 lb to 17.1 lb. The biggest drop was due to eliminating the Katalyn Hiker water filter and relying on tablets. I estimate food and water at 6.83 lb., so just under 24 lb total.

The 17.1 lb includes 8.9 oz of dog specific items, for a "net" baseweight of 16.54lb. Will be difficult to significantly improve without replacing tent, pack, and sleeping bag.